There is a form of punctuation called the semicolon. (It’s the one that looks like a comma with a period stacked on top of it.) In my time as a copyeditor I’ve slashed out more semicolons than I care to count, usually due to overuse or misuse. I prefer to think of the semicolon as a supercomma. It helps me to remember the proper usage of the beast.
So what is it?
A supercomma is the bastard child of the comma and the period. It’s the Long Pause. There are essentially two ways to use it.
The first, is to join two clumps of a sentence that could really stand as separate sentences in their own right. To check if you’re using this correctly, try replacing the supercomma with a period and see if it still looks grammatically correct… Then decide if you really need to use a supercomma, or if you can just leave the period there.
Used in this way, the supercomma helps to link the sentences together, but still provides that deep pause that a period would bring. It’s most commonly used when linking contrasting statements, showing a jump in thought within a sentence: “I really hate winter; my sister seems to love it.”
Be wary, however, of stringing sentences along in a giant conga-line of words. Periods give the reader time to gather their thoughts. Dragging out a sentence can result in the reader being unable to process the entire thing in one go, and makes reading a chore.
The second use of a supercomma is… well… as a super comma. You probably already know that when you list things out in a sentence, you put commas between them. Well, when you have to list things out that contain commas, it only confuses people to use more commas to space them out. That’s where the supercomma comes in.
You can use it for a list of things like cities: “I’ve lived in Backwards, FU; Nowhere, BO; and Cheeseburger, IC.” Or, if you’re being descriptive, for lists needing internal grammar: “I had dinner with my aunt, Maynard; my landlady, the one with the mole on her cheek; and a used car salesman, Stephanie.”
If you keep these examples in mind, and remember that the semicolon is just a supercomma, you should be much better able to decide when to use it in your writing. Good luck, and may the muse be with you.